The present invention relates to disposable absorbent articles, and more particularly to disposable absorbent articles having one or more graphics thereon, and processes and systems for making the same.
Traditionally, disposable absorbent articles, such as infant diapers or training pants, adult incontinence products and other such products, are constructed with a moisture-impervious outer backing sheet (or xe2x80x9cbacksheetxe2x80x9d), a moisture-pervious body-contacting inner liner sheet (or xe2x80x9ctopsheetxe2x80x9d), and a moisture-absorbent core (or xe2x80x9cabsorbent corexe2x80x9d) sandwiched between the liner sheet and the backing sheets. These disposable absorbent articles oftentimes include additional features such as elastic waist bands, elastic leg bands, and stretchable side panels. Further, decorative graphics can be incorporated into the disposable absorbent article for aesthetic and functional purposes.
Disposable absorbent articles are generally assembled on an automated production line by separately supplying the individual components of the absorbent article to the production line at predetermined locations along the machine direction, and layering the individual components to form an integrated absorbent article. Various known methods are available for bringing these individual components together so that the components in the integrated product are in a desired relation with respect to each other. In bringing these individual components together, various known methods have been used to sense the position of a particular component, and then to adjust the placement of subsequent components in order to properly position them with respect to the previously sensed component.
Illustratively, prior art methods for assembling components of absorbent articles have employed photo/optical techniques to sense reference markers on the individual components. The reference markers assist in cutting and placing the individual components onto the integrated absorbent article. The reference markers have typically been included in the final assembled product. This is so because the reference markers employed in prior techniques need to be sensed downstream in the production line to provide error correction, requiring complex feed-back control systems. However, the inclusion of the reference markers on the final assembled product can detract from the aesthetics of the product and are therefore not desirable. Further, the necessity to initially place the reference markers on the individual components is an added step that is not desirable.
The foregoing description of the various products, methods, and apparatus and their attendant disadvantages is in no way intended to limit the scope of the present invention, or to imply that the present invention does not include some or all of the various elements of the products, methods, and apparatus in one form or another. Indeed, various embodiments of the invention may be capable of overcoming some of the disadvantages noted herein, while still retaining some or all of the various elements of the products, methods, and apparatus in one form or another.
In response to the difficulties and problems encountered in the prior art, a method and system for making a disposable absorbent article having a graphic has been discovered.
In accordance with the present invention, there is provided an absorbent article including one or more graphics thereon, and a method and system for making the same. A digital picture is taken of the graphic. Based on the digital picture, a calculated centroid position of the graphic is determined. The calculated centroid position is compared with a target centroid position. Based on the variation of the calculated centroid position with the target centroid position, the processing is adjusted so as to apply the graphic as desired.
In accordance with a further aspect of the invention, a method is provided for disposing a graphic layer, including thereon a plurality of discrete graphics, on a product layer. The method comprises of providing a continuously moving graphic layer, the graphic layer having discrete graphics printed thereon; providing a continuously moving product layer of product; and inputting an input image of a graphic before the graphic is disposed on the product layer. The method further includes determining a calculated centroid position of the graphic based on the input image and comparing the calculated centroid position of the graphic with a target centroid position. Additionally, the method includes controlling the disposing of the graphic on the product layer based on the comparing.
These and other objects, features and advantages of the exemplary embodiments will become more readily apparent upon reading of the detailed description of the exemplary embodiments of this invention in conjunction with the following drawings.